The latest guidelines for kids and media use began with pushback from one local researcher.

In his TED talk a few years back, Dr. Dimitri Christakis used a Baby Einstein farm video—full of rapid scene cuts between nuzzling sheep, non sequitur cornfield images, and a random horse puppet—to illustrate how TV can overstimulate young kids and condition their minds to a faster pace than what they encounter in actual reality. Thanks to such hyperpaced programming, every hour of TV kids watch, on average, before age three increases their likelihood of attention problems by 10 percent.

Christakis doesn’t sound like a guy who would advocate rolling back the American Academy of Pediatrics’ ironclad “no screens for kids younger than two” recommendation—a guideline he helped author. And yet the director of the Center for Child Health, Behavior and Development at Seattle Children’s Research Institute was a driving force in the AAP’s new recommendations, which okay some screen use for kids as young as 18 months.

In 2014, the nationally known researcher made big waves in his tiny professional community with a journal article that challenged the prevailing wisdom that all screens are created equal. The research underpinning those old recommendations—much of it Christakis’s own work—predated the arrival of the tablet. As technology changed, he found himself giving parents advice that conflicted with the very guidelines he helped create: “We can’t possibly treat video chatting with Grandma the same way we treat watching the Power Rangers on television.”

That article sparked discussion that lead to the AAP’s official revision of screen time guidelines in October 2016. The group okays video chatting and high-quality (and slower-paced) educational programming for kids 18 to 24 months, but encourages parents to limit kids ages two to five to no more than an hour of screen time per day, down from two hours.

Meanwhile Christakis and his colleagues keep an eye on the next wave of technology likely to influence families in the future: “Virtual reality is already here, and it’s going to be a completely different immersive experience for babies.”